TY - JOUR
T1 - Biogeochemical Cycling of Colloidal Trace Metals in the Arctic Cryosphere
AU - Jensen, Laramie T.
AU - Lanning, Nathan T.
AU - Marsay, Chris M.
AU - Buck, Clifton S.
AU - Aguilar-Islas, Ana M.
AU - Rember, Robert
AU - Landing, William M.
AU - Sherrell, Robert M.
AU - Fitzsimmons, Jessica N.
N1 - Funding Information:
The authors would like to thank and acknowledge the Captain and crew of the USCGC , Dave Kadko and Greg Cutter for proposing and enabling cruise leadership, and GN01 Supertechnicians Gabi Weiss and Simone Moos for sample collection at sea. The authors thank Luz Romero for assistance with ICP‐MS analyses and maintenance and Angelica Pasqualini, Bob Newton, Peter Schlosser, and Tobias Koffman for contribution of their oxygen isotope measurements and freshwater model estimates used in the melt pond models. Additionally, this work would not have been possible without the SIO ODF team for salinity analyses. This work was supported by NSF Division of Ocean Sciences (OCE) award 1434493 and 1713677 to J. N. Fitzsimmons and R. M. Sherrell, 1438047 to C. S. Buck and W. M. Landing, and 1433717 to A. Aguilar‐Islas and R. Rember. N. T. Lanning was funded through an NSF REU experience (NSF OCE 1455851) as well as through the NSF Graduate Research Fellowship award 1746932. Healy
Funding Information:
The authors would like to thank and acknowledge the Captain and crew of the USCGC Healy, Dave Kadko and Greg Cutter for proposing and enabling cruise leadership, and GN01 Supertechnicians Gabi Weiss and Simone Moos for sample collection at sea. The authors thank Luz Romero for assistance with ICP-MS analyses and maintenance and Angelica Pasqualini, Bob Newton, Peter Schlosser, and Tobias Koffman for contribution of their oxygen isotope measurements and freshwater model estimates used in the melt pond models. Additionally, this work would not have been possible without the SIO ODF team for salinity analyses. This work was supported by NSF Division of Ocean Sciences (OCE) award 1434493 and 1713677 to J. N. Fitzsimmons and R. M. Sherrell, 1438047 to C. S. Buck and W. M. Landing, and 1433717 to A. Aguilar-Islas and R. Rember. N. T. Lanning was funded through an NSF REU experience (NSF OCE 1455851) as well as through the NSF Graduate Research Fellowship award 1746932.
Publisher Copyright:
© 2021. American Geophysical Union. All Rights Reserved.
PY - 2021/8
Y1 - 2021/8
N2 - The surface waters of the Arctic Ocean include an important inventory of freshwater from rivers, sea ice melt, and glacial meltwaters. While some freshwaters are mixed directly into the surface ocean, cryospheric reservoirs, such as snow, sea ice, and melt ponds act as incubators for trace metals, as well as potential sources to the surface ocean upon melting. The availability and reactivity of these metals depends on their speciation, which may vary across each pool or undergo transformation upon mixing. We present here baseline measurements of colloidal (∼0.003–0.200 μm) iron (Fe), zinc (Zn), nickel (Ni), copper (Cu), cadmium (Cd), and manganese (Mn) in snow, sea ice, melt ponds, and the underlying seawater. We consider both the total concentration of colloidal metals ([cMe]) in each cryospheric reservoir and the contribution of cMe to the overall dissolved metal phase (%cMe). Notably, snow contained higher (cMe) as well as higher %cMe relative to seawater for metals such as Fe and Zn across most stations. Stations close to the North Pole had relatively high aerosol deposition, imparting high (cFe) and (cZn), as well as high %cFe, %cZn, %cMn, and %cCd (>80%). In contrast, surface seawater concentrations of Cd, Cu, Mn, and Ni were dominated by the soluble phase (<0.003 μm), suggesting little impact of cMe from the melting cryosphere, or rapid aggregation/disaggregation dynamics within surface waters leading to the loss of cMe. This has important implications for how trace metal biogeochemistry speciation and thus fluxes may change in a future ice-free Arctic Ocean.
AB - The surface waters of the Arctic Ocean include an important inventory of freshwater from rivers, sea ice melt, and glacial meltwaters. While some freshwaters are mixed directly into the surface ocean, cryospheric reservoirs, such as snow, sea ice, and melt ponds act as incubators for trace metals, as well as potential sources to the surface ocean upon melting. The availability and reactivity of these metals depends on their speciation, which may vary across each pool or undergo transformation upon mixing. We present here baseline measurements of colloidal (∼0.003–0.200 μm) iron (Fe), zinc (Zn), nickel (Ni), copper (Cu), cadmium (Cd), and manganese (Mn) in snow, sea ice, melt ponds, and the underlying seawater. We consider both the total concentration of colloidal metals ([cMe]) in each cryospheric reservoir and the contribution of cMe to the overall dissolved metal phase (%cMe). Notably, snow contained higher (cMe) as well as higher %cMe relative to seawater for metals such as Fe and Zn across most stations. Stations close to the North Pole had relatively high aerosol deposition, imparting high (cFe) and (cZn), as well as high %cFe, %cZn, %cMn, and %cCd (>80%). In contrast, surface seawater concentrations of Cd, Cu, Mn, and Ni were dominated by the soluble phase (<0.003 μm), suggesting little impact of cMe from the melting cryosphere, or rapid aggregation/disaggregation dynamics within surface waters leading to the loss of cMe. This has important implications for how trace metal biogeochemistry speciation and thus fluxes may change in a future ice-free Arctic Ocean.
KW - Arctic Ocean
KW - colloids
KW - GEOTRACES
KW - melt ponds
KW - sea ice and snow
KW - trace metals
UR - http://www.scopus.com/inward/record.url?scp=85113621337&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85113621337&partnerID=8YFLogxK
U2 - 10.1029/2021JC017394
DO - 10.1029/2021JC017394
M3 - Article
AN - SCOPUS:85113621337
VL - 126
JO - Journal of Geophysical Research: Oceans
JF - Journal of Geophysical Research: Oceans
SN - 2169-9275
IS - 8
M1 - e2021JC017394
ER -